Method of making leakproof packages



June 25, 1946. R. GUYER 2,402,548

METHOD OF MAKING LEAKPROOF PACKAGES Filed May 5, 1943 4 Sheets-Sheet l A WI.............,......).-.}\

. .illffllllllllllllllllia In R. GUYER METHOD 0F MAKING LEAKPROOF PACKAGES June 25, 1946.

4 Sheets-Sheet 2 Filed May 5, 1945 June 25, 1946. R GUYER 2,402,548

METHOD OF MAKING LEAKPROOF PACKAGES Filed May 5, 1945 4 Sheets-Sheet 5 Elma/m43 June 25, 1946. R. GUYER METHOD OF MAKINGYLEAKPROOF PACKAGES Filed May 5, 1943 4 Sheets-Sheet 4 Patented June 25., 1946 METHOD F MAKING LEAKPROOF PACKAGES- Reynolds Guyer, St. Paul, Minn., assigner to Waldorf Paper Products Company, Bt. Paul, Minn., a corporation of Minnesota Application May 5, 1943, Serial No. 485.726

s claims. 1

My invention relates to an improvement in leak-proof package construction and method of forming the same, wherein it is desired to provide a carton which will not leak or sift.

In packaging powdered or pulverized material in cartons formed of cardboard sheet material, or the like, dimculty has been experienced in so sealing the cartons as to render them sift-proof. In the use of rectangular cartons to contain nely powdered or pulverized material, most of the dimculty is experienced at the corners of the carton and adjacent the corners thereof. I have found that if the carton corners can be effectively sealed, such boxes will, for the most part, be rendered sift-proof.

It is the object of the present invention to provide a carton or box construction formed of fiat sheet-like material and having the corners thereof molded by pressure, and preferably with heat to effectively seal these corners. As a result the points where siftingV is most. likely te occur are rendered leak-proof and sift-proof, and most of the diiiiculty experienced through the use of such cartons may be eliminated.

Most types of cardboard cartons used for containing powdered or pulverized material are provided with rectangularly arranged side walls having end flaps hingedly secured thereto. These end ilaps are ordinarily folded to overlie one another and sealed with a suitable adhesive. The present invention also embodies the idea of molding the exposed free edges of such closing flaps so as to eectively seal these free edges to the body of the carton to prevent sifting between these flaps, and between the flaps and the body of the carton.

A further feature of the present invention lies Y in the fact that the portions of the carton to be molded may be moistened before the actual molding operation. Cartons formed of cardboard and the like, composed of fibrous cellulosic materials, often have a tendency to soften when wet. When in this softened condition the pulp or fibrous cellulosic material can be effectively molded together under pressure and heat. Thus the fibers of the various layers of material found at the corners of the carton will, to some extent, unite together when pressure and heat is applied so as to cause a bond between the various layers of cellulosic material which will prevent separation between layers.

A further feature of the present invention lies in the fact that a coating placed upon the surface of the carton after the same is sealed may be caused to impregnate the cellulosic fibers along the corners and edges of the carton when heat and pressure are applied. For example, a carton formed of cardboard, when dipped in a waterproofing coating of wax or similar material, may be subjected to heat and pressure to cause the wax or like substance to impregnato into specified areas of the cellulosic material. Such a carton after being dipped may be compressed by suitable die means to cause the water-proofing coating to impregnate into the area of the carton contacted by the die. This is particularly true when the die is heated. The coating therefore not only acts to coat the outer surfaces of the carton, but also to fill any interstices between adjacent flaps or carton portions to prevent sifting of the material contained.

When filled in the usual manner, a carton may sift at the corners, particularly upon compression of the sides of the container in a manner to tend to decrease the volume thereof. After such a carton has been dipped into a coating solution so as to provide a substantially continuous exterior coating the carton may still sift to some extent. However, I have found that when such a carton is compressed in a heated die so as to press the corners of the carton together and so as to seal the edges of the superimposed sealing flaps, al1 of the interstices through which the powdered or pulverized material ordinarily sifts may be effectively sealed. This action is caused by the molding of the fibrous material together and also by the impregnation of the coating into the fibrous material in a manner to form an effective bond so as to seal the laminations together.

These and other objects and novel features of my invention will be more clearly and fully set forth in the following specication and claims:

In the drawings forming a part of my specication:

Figure 1 is a perspective view of a. carton embodying the features of my invention.'

Figure 2 is a sectional view through a corner of the carton, the position of the section being indicated by the line 2-2 of Figure 1.

Figure 3 is a sectional view through the top and bent side of the carton, the position of the section being indicated by the line 3-3 of Figure 1.

Figure 4 illustrates a sectional view similar to Figure 2, but showing a coated carton before the molding operation has taken place.

Figure 5 is a sectional view similar to Figure 3, but showing a coated carton before the molding operation has taken place.

Figure 6 is a view similar to Figure 4 showing 3 the construction after thel molding operation has taken place;

Figure 'I is a sectional view similar to Figure 5 showing the construction after the molding operation has taken place.

Figure 8 is a sectional vilew similar to Figurel showing a box or carton which has been molded and then coated with a water-proof coating.

Figure 9 is a-view similar to Figure 2 showing a sectional view of a molded carton which has been coated after the molding operation.

Figure l is a perspective view of a carton and liner which is suitable for molding purposes.

Figure 11 is a cross-sectional view through the carton and liner illustrated in Figure 10.

Figure 12 is a sectional view of the carton shown in Figures and 11 after the molding operation.

Figure 13 is a sectional view showing the carton of Figures 10 and 11 after the molding operation.

Figure 14 is a perspective view of a modified form of molded carton construction.

Figure l5 is a sectional view through the top and side of the carton shown in Figure 14, the position of the section being indicated by the line I5-I5 of Figure 14.

Figure 16 is a diagrammatic view, partly in section, showing a die arrangement for molding the corners of a, completed carton.

Figure 17 is a view similar to Figure 16 showing the die in its molding operation.

Figure 18 is a diagrammatic plan of the carton blank for the particular carton illustrated.

The carton A, illustrated in Figure 1 of the drawings, may be of any common or usual type. In the figures illustrated the carton A is generally rectangular in form, having parallel front and rear panels I0 and II connected by parallel side panels I2 and I3. 'I'he panel II is connected to the panel I3 along the fold line I4. A side panel I3 is connected to a front panel I0 along the fold line I5. 'I'he panel I 0 is connected tothe side panel I2 along the fold line I6. The panell2 is connected to an overlapping glue flap I1 along the fold line I3.

End closing flaps are provided for the box A. 'I'hese flaps may be of any suitable or usual type and in the construction illustrated, a pair of opposed sealing flaps 20 and 2| are connected to the top of the sides I2 and I3 along fold lines 22 and 23. Similarly, closing flaps 24 and 25 are connected to the upper edge of the panels III and i I along fold lines 2B and 21.

Opposed closing flaps 29 and 30 are connected to the lower edges of the sides I2 and I3 along fold lines 3| and 32. Similarly, closing flaps 33 and 34 are connected to the lower edge of the panels I0 and II along fold lines 35 and 35. In the construction illustrated, the walls I0, II, I2 and I3 are folded into rectangular shape and the pairs of opposed flaps 20 and 2|, and 29 and 30 on the upper and lower edges respectively, of the box are folded inwardly into substantially abutting relationship. One of the other sealing panels at each end of the box, such as the flaps 24 and 33 are folded to overlie the opposed side flaps and are adhered thereto. The remaining flaps and 34 are folded to overlie the flaps 24 and 33 and are adhered thereto.

A rectangular carton of usual or common construction is thus formed. While a. specific type of carton has been described it is obvious that this particular type of carton is not important to the invention and that other types may be substituted therefor.

lao

In a'rectangular carton of the type disclosed it is difficult to prevent finely divided material such as powder and the like from sifting out of the box, particularly at the corners thereof and through the external seams. Little sifting usually takes place between the glue flap I1 and the panel II due to the fact that this seam is glued while the carton is flat and sufficient pressure may be applied at the seam to effectively seal the flap i1 to the panel I I. In gluing the various closing flaps, however, in production it is difhcult to apply a compression force sufficient to glue the various aps together throughout their entire area. This `difllculty is increased by the tendency of the flaps to curl when moistened with the glue. I therefore desire to mold the corners of the carton so as to more effectively connect the various laminations of material at the corners and to seal any small openings through the carton at the corners which might otherwise result in sifting of the contents of the package.

There are several types of apparatus which may be used to accomplish the desired result. An ironing means which is preferably heated and which engages the corners of the box to bend the same inwardly will accomplish the result. For the sake of speed of production, however, it is usually preferable to mold all of the, corners of the carton simultaneously in some type of die means, such as that diagrammatically illustrated in Figures 16 and 17 of the drawings.

These figures of the drawings show a pair of gripping fingers 31 for supporting the carton A and a pair of vertically reciprocable die members 33 and 40 positioned above and below the carton A respectively. By reciprocating these die members 39 and 40 together from the position illustrated in Figure 16 of the drawings, the dies may engage the opposite ends of the carton A, as

40 illustrated in Figure 17 of the drawings, thus compressing the carton between the dies and ironing the ends of the box so as to round the corners and edges thereof. 'I'his action tends to compress the fibrous material of which the box is formed inwardly, condensing the fibrous structure along the upper and lower edges of the carton and particularly at the corners thereof, squeezing the fibrous material of which the box is formed together at these points, and closing any openings through the carton at this point.

In accomplishing my method in the simplest form, I desire first to merely compress or iron the ends of the container by compressing them between the die means 39 and 40 after the cartons have been filled and sealed. I have found it preferable, however, to moisten the material of which the box is formed so as to revert the fibrous material into combinable form before the molding operation. If the surface of the container adjacent the corners and external seams is moistened, this moisture softens the brous structure of the paper and provides a tendency for the individual fibers forming the carton sheet material to separate. When placed in the forming die, which is preferably heated, not only does the moisture simplify the molding operation, but also Athe heated die tends to unite the compressed fibers together under pressure in a manner to cause the fibers to remain in molded shape.

Figure 2 illustrates a section through a corner of the container after the molding operation. I t will be noted that three laminations of material form the top of the carton due to the manner in which the aps are folded. By moistening the fibrous material at the corner the vfibers of unitary construction in which the laminstions are lvirtually This is also true of theedsesoftheboxasillustratedinl'igiw 'lhe moistenedlaminations when subiectedto heat and pressure have a tendency to knit together along the compressed edge; thus tightly sealing the laminations together, particularly where external lseams occur.

Inl'igures4through 'lofthedrawingsIdisnumeral Il. I have found that when a carton .is dipped in coating material such as wax for example, and then subjected to heat and pressure by dies, such as those illustrated in Figures Asillustratedin to reinforce the sides of the shell-so that this Outer shell may be formed of relatively thin material. At the same time, however, the 'shell II- v will effectively support the shell I3 when the cor- I cloeeaeartonconstructionformedbyamethod ners thereof are molded in any one of. the manners previously described. In the construction illustrated the carton is dipped in wax after the sealing operation thereof and' the end's of the carton are subsequently inolded-` into the form illustrated'in Figures 12 and 13 of the drawings after 'the dipping operation.

16 and 17 of the drawings, a portion of the wax coating will be forced into thel laminations of material at the corners and along the edges ofthecarton in a manner to impregnate the material with a water-proofing compound. Furthermore, this water-proong compound has a tendency to stifien or reinforce the corners and edges of the carton tending to maintain therounded construction of the carton at the corners and edges. I have found that cartons formed of ordinary cardboard dipped in paraiiln wax and molded as illustrated in Figures 8 and 7 of the drawings will resist moisture ion to the interior of the carton even though the carton be sub.- merged in water. Similar cartons not having molded corners and edges have similarly beenV dipped in wax. but haye been unable to withstand transmission of moisture. vInFiguresliand901'thedrawings,Idisclose diagrammatically a carton C which is identical with the carton A,`with the exception that after the corners of the carton have been molded the same is dipped into a water-proofing solution such as wax. The carton C thus differs from the carton B only in the time at which the wax coating is applied. The coating 42 of the carton C is applied after the molding operation, while the coating Il of the carton B is applied before the molding operation.

In Figures 10 through 13 I disclose a carton D which differs from the carton A only in the fact that the carton is provided with an interior reinforcing sleeve. The carton D comprises a shell 4l which is identical with the carton A formed ,from the blankillustrated in Figure r1&8 of the drawings. A rectangular shell 44 is slipped into the shell 43 in order to reinforce the same durl ing the molding or compression operation.

In Figuresle and 15 of the drawings I'disclose a modified form of construction in which opposed edges of the container are molded in a somewhat `dierent manner. In this form of construction,

as in all of the other forms thereof.' the` cartonl molded may be of any usual type such as the one illustrated in Figure 18 ofthe drawings. In the form illustrated. pressure is applied to the laminated top of the box and other front and rear panels thereof I0 and l-I respectively, to compress the edges thereof together. For example, opped rollers may engage the carton along the fold linesl 2l and 21 to compress these edges together. the edges :fand 21 are compressed by heat and pressure which tends to mold the laminations forming the carton together at these points. The carton is preferably moistened before the molding operation and if e, coating such as It is desired, this ycoating may be applied either before or after the molding operation.

' larly true if the carton is coated before the molding operation and the coating usually liquiiies to some extent during the molding operation and acts in somewhat the same manner as water to loosen the ber structure of the carton forming material before lthe molding operation.

In accordance with the patent statutes, I have described the principles of construction of my carton and the method of forming the same, and while I have endeavored to set forth the best embodiments thereof,`1 desire to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of my invention.

I claim:

1. The method of sealing a carton of nbrous material having ,avplurality oi' panels connected together, three adjoining panels coming together to form a corner therebetween; the method consisting of applying inward pressure to the apex of the corner to compress the material-inwardly toward the interior of the carton and to compact the fibrous structure at the corner, the pressure being sufficient to compact the bers and insuiiicient to rupture the iibrous structure.

,2. 'I'he method of sealing a carton of fibrous material having a plurality of panels connected together, three adjoining panels coming together to form a corner therebetween; the method consisting of applying inward pressure and heat-to the apex of the comer to compress the materialV inwardly toward the interior of the carton and to compact the fibrous structure at the corner.

3. The method of sealing a carton of fibrous material having a plurality of panels connected together, three adjoining panels coming together il to a glue flap Il which lmderlies a portion of the panel ll which is secured thereto by means of asultable adhesive.

to form a corner therebetween the method consisting of coating the carton, and applying inward 76 pressure to the apex ofthe corner-to compress Figurel ofthedrawingsthe sleeve il nts closelywithinthe shellllandacts- The rollers are preferably heated so that' the material inwardly toward the interior of the carton and to compact the fibrous structure at the corner. l

4. The method of 4sealing a carton of brous material having a. plurality oi' panels connected to form a corner therebetween; the method conofthe carton and to compact the iibrous struc.-

ture. at these corners.

sisting of coating'the carton, and applying inward pressure and heat to the apex o'i the corner to compress the material inwardly toward the interior of the carton and to compact the ibrousy material having side walls and end closing means which comprises applying heat and pressure inwardly to the corners of the carton to press the' apex of the corner inwardlytoward the interior 7-.'The method of sealing a carton of lbrous material having a plurality o f panels connected together,.three adjoining panels coming together to form a corner therebetween, the carton. having a coating thereon; the method consisting of applying inward pressure to the apex of the comer to compress the material inwardly toward the interior of the carton and to compact the iibrous structure at the corner, the pressure being sumcient to compact the iibers and insuii'icient to rupture the brous structure.

8. 'I'he method of sealing a carton of iibrous material having a vplurality-of panels connected together, three, adjoining panels coming together to form a corner` therebetween, the carton having a coating thereon; the method consisting of applying inward pressure and heat to the apex of the corner to compress the material inwardly toward the interior of the carton and to compact the 'nbrous structure at the corner.

' lmznmoms GUYER. 

